Medical instruments, instruments used in orthodontics, and instruments for several other fields, particularly hand held instruments, must often be made of strong corrosion resistant metals such as titanium, titanium alloys, or stainless steel. Such materials are frequently difficult to machine and therefore present problems in the fabrication of the instrument parts from the raw material stock. Because hand held instruments used in medicine and dentistry require a combination of flat and curved surfaces, the instrument manufacturing processes of the past have required the performance of combinations of cutting, milling and grinding steps on the hard raw material, contributing substantially to the cost of the manufacture of such instruments of such materials compared to the manufacture of similar tools of other steels and materials.
Hand held instruments such as cutters and pliers require the application of at least moderate force by the user. For example, in orthodontics, orthodontic pliers used in the bending of archwires and the manipulation of other parts of orthodontic appliances require not only a delicate use of the plier instrument, but the exertion of considerable force from the user's hand. Thus, the manufacture of such instruments with rounded handles has been regarded as necessary to allow orthodontists to use such instruments effectively and with comfort. Because such instruments must be resistant to contamination and are subjected to high sterilization temperatures, the bonding of more easily shaped organic materials to the handles and other parts of the instrument is not desirable.
Typically, a stainless steel tool, such as a pair of pliers, is made from a block or bar stock of raw material of rectangular cross-section. The components of the instruments, in the case of pliers, include two nearly identical parts cut from the stock raw material. The cut parts are then shaped and machined into the components of the instrument. The handle portion of such an instrument, and other outside surfaces, are then rounded by a process such as grinding, to remove the 90.degree. corners where the tool contacts the users hand. The rounding process leaves a curved contour that can be gripped with considerable force without subjecting the user to discomfort or interfering with the use of the tool. The curved surfaces are also provided on the parts of the tool that contact the patient, for the comfort of the patient and to protect the patient from injury. Such grinding and other machining process required to impart the curved outer surfaces to instruments made of such difficult to machine materials substantially adds to the increased cost of instruments made of such metals.
Accordingly, there is a need for a better and less costly method of fabricating instruments out of metals and other materials that are difficult to machine where curvature of certain surfaces of the finished instrument is desired.